Aeroplane Equipment and Instruments — Page 78, Lesson 123

I want to walk you through the aeroplane equipment and instruments that are critical for accident investigation — specifically the Cockpit Voice Recorder, or CVR, and the Flight Data Recorder, or FDR. Let’s start with the CVR. The reason we carry these devices is that the transcript of communications — both to and from the aeroplane, and between crew members — often provides vital evidence of what happened during an incident or before an accident. So, to assist investigations, CVRs are required to be carried and operated at all times in aircraft involved in CAT — that’s Commercial Air Transport. The regulation that governs this is EU-OPS, and it lays out three specific cases for when a CVR must be fitted. Case 1 applies to multi-engine turbine aircraft issued with a Certificate of Airworthiness, or CofA, on or after 1 April 1998, and with a maximum passenger seating capacity of more than 9. For those aircraft, the CVR must record at least the last 30 minutes. However, there’s an important extension: for any aircraft — turbine or piston — registered after that same date with a Maximum Take-Off Mass, or MTOM, in excess of 5700 kg, the recording limit is extended to 2 hours. Case 2 covers multi-engine turbine aircraft with a CofA issued between 1 January 1990 and 31 March 1998, again with a max passenger seating capacity of more than 9. In this case, the recorder must record at least the last 30 minutes. Case 3 applies to any aircraft with a CofA issued before 1 April 1998 and an MTOM greater than 5700 kg. Here, the recorder must also record for at least the last 30 minutes. Let me summarise that for you. All aeroplanes over 5700 kg MTOM are covered by Case 3. From 1 January 1990, the rule expanded to include multi-engine turbine powered aeroplanes under 5700 kg MTOM but with more than 9 passenger seats — that’s Case 2. And from 1 April 1998, the recording time increased to 2 hours for aeroplanes over 5700 kg MTOM. Now, let’s look at the operation, construction, and installation of CVRs. They have to be constructed, located, and installed so as to provide maximum practical protection for the recordings — the goal is that the recorded information can be preserved, recovered, and transcribed. Flight recorders must meet prescribed crashworthiness and fire protection specifications. They are also required to have a device fitted to assist underwater location. As for when they operate, CVRs must switch on automatically prior to the aeroplane first moving under its own power, and they continue to record until the termination of the flight. Moving on to Flight Data Recorders, or FDRs. These are more commonly referred to as the ‘black box’, although they are usually painted a Day-Glo colour — either red or yellow — and they have underwater location devices fitted. FDRs are required to be capable of recording data pertaining to the operation of the aeroplane systems, control positions, and performance parameters. Just like CVRs, they are required to assist in the investigation of accidents and incidents.